Speed Conversion Calculator

Speed is the rate of change in position of an object, regardless of direction of travel. Walk forward or backward at 2 meters per second, and your speed is just that: 2 m/s. Velocity is speed in the context of direction. Say you were walking backward again; your velocity is negative 2 m/s, although your speed is still positive.

For most science applications, the SI unit for speed and velocity is meters per second (m/s), although kliometers per hour (km/h) is sometimes used when measuring the speed of vehicles. The English system usually expresses speed as miles per hour (mph) or sometimes feet per second (ft/s), while marine vessels typically use knots, or nautical miles per hour.

How to Convert Units of Speed

Conversions are performed by using a conversion factor. By knowing the conversion factor, converting between units can become a simple multiplication problem:

S * C = E

Where S is our starting value, C is our conversion factor, and E is our end converted result.

To simply convert from any unit into meters per second, for example, from 5 mph, just multiply by the conversion value in the right column in the table below.

5 mph * 0.44704 [ (m/s) / (mph) ] = 2.2352 m/s

To convert from m/s into units in the left column divide by the value in the right column or, multiply by the reciprocal, 1/x.

2.2352 (m/s) / 0.44704 [ (m/s) / (mph) ] = 5 mph

To convert among any units in the left column, say from A to B, you can multiply by the factor for A to convert A into meters per second then divide by the factor for B to convert out of meters per second. Or, you can find the single factor you need by dividing the A factor by the B factor.

For example, to convert from miles per hour to kilometers per hour you would multiply by 0.44704 then divide by 0.2777778. Or, multiply by 0.44704/0.27777778 = 1.6093439. So, to convert directly from mph to km/h (kph), you multiply by 1.6093439.

Units, symbols and conversion values used in this speed calculator To Convert from Unit Unit Symbol and Convert to ( m/s2 or m/(s·s) ) Multiply by ( m/s 2 / Unit ) centimeter per minute cm/min meter per second 0.0001667 centimeter per second cm/s meter per second 0.01 foot per hour ft/h meter per second 8.46667E-05 foot per minute ft/min meter per second 0.00508 foot per second ft/s meter per second 0.3048 inch per minute in/min meter per second 0.000423333 inch per second in/s meter per second 0.0254 kilometer per hour km/h (kph) meter per second 0.2777778 kilometer per second km/s meter per second 1000 knot (nautical mi/h) kn meter per second 0.5144444 knot (UK) kn meter per second 0.5148 meter per hour m/h meter per second 0.0002777778 meter per minute m/min meter per second 0.01667 meter per second m/s meter per second 1 mile per hour mi/h (mph) meter per second 0.44704 mile per minute mi/min meter per second 26.8224 mile per second mi/s meter per second 1609.344 speed-of-light (vacuum) c meter per second 299792458 yard per hour yd/h meter per second 0.000254 yard per minute yd/min meter per second 0.01524 yard per second yd/s meter per second 0.9144

References/ Further Reading

The National Institute of Standards and Technology (NIST) - The NIST Guide for the use of the International System of Units - Appendix B, subsections B.8 Factors for Units Listed Alphabetically and B.9 Factors for units listed by kind of quantity or field of science.

Lide, David R., Daniel (Editor-in-Chief). CRC Handbook of Chemistry and Physics, 89th Edition New York, NY: CRC Press, p. 1-28, 2008.

Wikipedia contributors. "Conversion of units" Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited 26 Jun. 2011.

How Many? A dictionary of units of measurement at http://www.ibiblio.org/units/ accessed 2023-07-25